Inkjet printing apparatus and recovery method

ABSTRACT

The inkjet printing apparatus includes: a printing unit to eject ink; a wiping unit capable of wiping an ejection opening surface by moving relative to the ejection opening surface with an opening, adapted to be in contact with the ejection opening surface, put in contact with the ejection opening surface; a suction unit connected to the wiping unit and configured to apply negative pressure to the ejection opening surface via the opening; a moving unit to move the wiping unit relative to the ejection opening surface; and a control unit to perform suction wiping operation by wiping the ejection opening surface with the wiping unit while applying negative pressure to the ejection opening surface. The control unit determines the timing to perform the suction wiping operation, and, according to the timing, determines a moving speed of the moving unit and a pressure value caused by the suction unit.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to inkjet printing apparatuses that ejectink onto print media to perform printing and recovery methods forkeeping favorable the condition of ink ejection from the print headwhich ejects ink and also for recovering it.

Description of the Related Art

Japanese Patent Laid-Open No. 2011-104864 discloses an inkjet printingapparatus including a wiper unit capable of wiping while sucking. Thisinkjet printing apparatus performs what is called vacuum wiping in whicha wiper unit is brought into contact with the print head, and performswiping on the ejection opening surface on which ejection openings forejecting ink are formed while performing sucking on the ejection openingsurface with a suction pump. In this operation, the wiper unit is movedin the forward and backward directions, and the forward movement isperformed with the higher negative pressure and the lower moving speedthan the backward movement in order to ensure removal of ink and foreignobjects and reduce the work time.

Meanwhile, vacuum wiping is performed, for example, in the followingthree cases: a case of removing foreign objects such as paper dustattached around the ejection openings or pushed into the ejectionopenings, a case of removing ink thickened in the ejection openings, anda case of removing bubbles generated in the ejection openings. Toefficiently execute removal for each purpose in those three cases, thevalue of the negative pressure applied to the ejection openings and theoperation time need to be set differently among the cases.

Unfortunately, the technique disclosed in Japanese Patent Laid-Open No.2011-104864 is only a technique in which the value of applied negativepressure and the moving speed of the vacuum wiper are set differentlybetween in the forward movement and in the backward movement in vacuumwiping, and hence, removal for each purpose cannot be executedefficiently.

SUMMARY OF THE INVENTION

The present invention provides an inkjet printing apparatus and recoverymethod capable of executing efficient vacuum wiping.

In the first aspect of the present invention, there is provided aninkjet printing apparatus comprising:

a printing unit having an ejection opening surface on which multipleejection openings configured to eject ink are arrayed;

a wiping unit that has an opening and is capable of wiping the ejectionopening surface by moving in a predetermined direction relative to theejection opening surface with the opening in contact with the ejectionopening surface;

a suction unit connected to the wiping unit and configured to applynegative pressure via the opening to the ejection opening surface incontact with the opening;

a moving unit configured to move the wiping unit in the predetermineddirection relative to the ejection opening surface; and

a control unit configured to perform suction wiping operation by wipingthe ejection opening surface with the wiping unit while driving thesuction unit to apply negative pressure to the ejection opening surface,wherein according to timing at which to perform the suction wipingoperation, the control unit determines a moving speed of the wiping unitby the moving unit and a negative pressure value applied by the suctionunit.

In the second aspect of the present invention, there is provided aninkjet printing apparatus comprising:

a printing unit having an ejection opening surface on which multipleejection openings configured to eject ink are arrayed;

a wiping unit that has an opening and is capable of wiping the ejectionopening surface by moving in a predetermined direction relative to theejection opening surface with the opening in contact with the ejectionopening surface;

a suction unit connected to the wiping unit and configured to applynegative pressure via the opening to the ejection opening surface incontact with the opening;

a moving unit configured to move the wiping unit in the predetermineddirection relative to the ejection opening surface;

a control unit configured to perform suction wiping operation by wipingthe ejection opening surface with the wiping unit while driving thesuction unit to apply negative pressure to the ejection opening surface;and a pressure detection unit configured to detect a pressure valueapplied by the suction unit, wherein the control unit controls thesuction wiping operation based on the pressure value detected by thepressure detection unit.

In the third aspect of the present invention, there is provided arecovery method used in an inkjet printing apparatus including aprinting unit having an ejection opening surface on which multipleejection openings configured to eject ink are arrayed and a wiping unitfor wiping the ejection opening surface, the recovery method being forrecovering ejection performance of the ejection openings by performingsuction wiping operation in which the wiping unit is being movedrelative to the ejection opening surface in a state where a suction unitis driven to apply negative pressure to the ejection opening surface,comprising determining, according to timing at which to perform thesuction wiping operation, a moving speed of the wiping unit and anegative pressure value applied by the suction unit.

The present invention makes it possible to execute efficient vacuumwiping (suction wiping operation).

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view of a printing apparatus in a standby state;

FIG. 2 is a diagram of a control configuration of the printingapparatus;

FIG. 3 is a view of the printing apparatus in a print state;

FIGS. 4A, 4B, and 4C are views of a conveying path of a print medium fedfrom a first cassette;

FIGS. 5A, 5B, and 5C are views of a conveying path of a print medium fedfrom a second cassette;

FIGS. 6A, 6B, 6C, and 6D are views of views of a conveying path used ina case of performing a print operation on the back surface of a printmedium;

FIG. 7 is a view of the printing apparatus in a maintenance state;

FIGS. 8A and 8B are perspective views illustrating the configuration ofa maintenance unit;

FIGS. 9A and 9B are schematic configuration diagrams of a vacuum wiper;

FIGS. 10A and 10B are explanatory diagrams of a carriage movementmechanism;

FIGS. 11A and 11B are explanatory diagrams of a suction mechanism forthe vacuum wiper;

FIGS. 12A, 12B, 12C, and 12D are explanatory diagrams for the contactbetween an ejection opening surface and the vacuum wiper;

FIG. 13 is a diagram illustrating pressure fluctuation during vacuumwiping;

FIG. 14 is a flowchart illustrating detailed process procedure of avacuum wiping process; and

FIG. 15 is a flowchart illustrating detailed process procedure of amanagement process.

DESCRIPTION OF THE EMBODIMENTS

Hereafter, embodiments of the present invention will be described indetail with reference to the drawings. The following embodiments are notintended to limit the present invention, and all the combinations of thefeatures described in the present embodiments are not necessarilyessential for the solutions provided by the present invention. Note thatthe relative positions, shapes, and the like of the constituentsdescribed in the embodiments are mere examples, and hence they are notintended to limit the scope of the invention only to those examples.

FIG. 1 is a view of the internal configuration of an inkjet printingapparatus 1 (hereinafter, the printing apparatus 1) used in thisembodiment. In FIG. 1, an x direction represents a horizontal direction,a y direction (direction normal to the sheet surface) represents adirection in which ejection ports are aligned in a later-described printhead 8, and a z direction represents the vertical direction.

The printing apparatus 1 is a multifunction printer including a printunit 2 and a scanner unit 3. The printing apparatus 1 can use the printunit 2 and the scanner unit 3 separately or in synchronization toperform various processes related to print operation and scan operation.The scanner unit 3 includes an automatic document feeder (ADF) and aflatbed scanner (FBS) and is capable of scanning a documentautomatically fed by the ADF as well as scanning a document placed by auser on a document plate of the FBS. The present embodiment is directedto the multifunction printer including both the print unit 2 and thescanner unit 3, but the scanner unit 3 may be omitted. FIG. 1 shows theprinting apparatus 1 in a standby state in which neither print operationnor scan operation is performed.

A first cassette 5A and a second cassette 5B that house print media (cutsheets) S are mounted in an attachable and detachable manner at a bottomportion of the print section 2 on the lower side of a housing 4 in thevertical direction. The first cassette 5A houses relatively small printmedia of up to a size of A4 in the form of a flat pile. The secondcassette 5B houses relatively large print media of a size of up to A3 inthe form of a flat pile. Near the first cassette 5A, a first feed unit6A is provided which separately feeds the housed print media. Likewise,a second feed unit 6B is provided near the second cassette 5B. When aprint operation is performed, a print medium S is fed selectively fromone of the cassettes.

Conveying rollers 7, a discharge roller 12, pinch rollers 7 a, spurs 7b, a guide 18, an inner guide 19, and a flapper 11 are conveyingmechanisms (conveying unit) that guide print media S in predetermineddirections. The conveying rollers 7 are drive rollers disposed upstreamand downstream of the print head 8 and driven by a conveying motor notillustrated. The pinch rollers 7 a are driven rollers that rotate whilenipping a print medium S with the conveying rollers 7. The dischargeroller 12 is a drive roller disposed downstream of the conveying rollers7 and driven by a conveying motor not illustrated. The spurs 7 b conveya print medium S while holding it between themselves and the conveyingrollers 7 disposed downstream of the print head 8 and the dischargeroller 12.

The guide 18 is provided along a conveying path for print media S andguides a print medium S in predetermined directions. The inner guide 19is a member extending in the y direction and having a curved sidesurface and guides a print medium S along this side surface. The flapper11 is a member that switches the direction of conveyance of a printmedium S in a double-sided print operation. A discharge tray 13 is atray on which to place and hold print media S discharged by thedischarge roller 12 after completing their print operations.

The print head 8 of in the embodiments is a full-line color inkjet printhead, in which the ejection openings capable of ejecting ink accordingto print data are arrayed along the y-direction of FIG. 1 by the lengthcorresponding to the width of a print medium S. Specifically, the printhead 8 is configured to be capable of ejecting ink of multiple colors.In the state in which the print head 8 is at a standby position, theejection opening surface 8 a of the print head 8 faces verticallydownward and is capped with a cap unit 10 as illustrated in FIG. 1. Inprint operation, the orientation of the print head 8 is changed by aprint controller 202 described later such that the ejection openingsurface 8 a faces a platen 9. The platen 9, composed of a flat plateextending in the y-direction, supports a print medium S from its backsurface while the print head 8 is performing print operation on theprint medium S. The movement of the print head 8 from the standbyposition to a printing position will be described later in detail.

An ink tank unit 14 stores inks of four colors to be supplied to theprint head 8. An ink supply unit 15 is provided at a point along a flowchannel connecting the ink tank unit 14 and the print head 8 and adjuststhe pressure and flow rate of the inks inside the print head 8 withinappropriate ranges. This embodiment employs a circulatory ink feedsystem. The ink supply unit 15 adjusts the pressure of the inks to besupplied to the print head 8 and the flow rate of the inks collectedfrom the print head 8 within appropriate ranges.

A maintenance unit 16 includes the cap unit 10 and a wiping unit 17 andoperates them with a predetermined timing to perform a maintenanceoperation on the print head 8. The maintenance operation will bedescribed later in detail.

FIG. 2 is a block diagram illustrating a control configuration in theprinting apparatus 1. The control configuration mainly includes a printengine unit 200 that controls the print section 2, a scanner engine unit300 that controls the scanner section 3, and a controller unit 100 thatcontrols the whole printing apparatus 1. The print controller 202controls various mechanisms of the print engine unit 200 in accordancewith instructions from a main controller 101 of the controller unit 100.Various mechanisms of the scanner engine unit 300 are controlled by themain controller 101 of the controller unit 100. Details of the controlconfiguration will be described below.

In the controller unit 100, the main controller 101, configured of aCPU, controls the entire printing apparatus 1 by using an RAM 106 as awork area in accordance with programs and various parameters stored inan ROM 107. For example, upon input of a print job from a host apparatus400 through a host I/F 102 or a wireless I/F 103, an image processingunit 108 performs predetermined image processing on received image datain accordance with an instruction from the main controller 101. The maincontroller 101 then transmits the image data after the image processingto the print engine unit 200 through a print engine I/F 105.

Meanwhile, the printing apparatus 1 may obtain image data from the hostapparatus 400 by means of wireless communication or wired communicationor from an external storage device (such as a USB memory) connected tothe printing apparatus 1. The communication method used for the wirelesscommunication or the wired communication is not particularly limited.For example, Wireless Fidelity (Wi-Fi) (registered trademark) orBluetooth (registered trademark) can be employed as the communicationmethod used for the wireless communication. Also, universal serial bus(USB) or the like can be employed as the communication method used forthe wired communication. Further, for example, upon input of a readcommand from the host apparatus 400, the main controller 101 transmitsthis command to the scanner section 3 through a scanner engine I/F 109.

An operating panel 104 is a mechanism with which the user inputs andreceives information into and from the printing apparatus 1. Through theoperating panel 104, the user can instruct the controller unit 100 toperform operations such as photocopying and scanning, set a print mode,check information on the printing apparatus 1, and so on.

In the print engine unit 200, the print controller 202, configured of aCPU, controls various mechanisms of the print section 2 by using an RAM204 as a work area in accordance with programs and various parametersstored in an ROM 203. Upon receipt of various commands and image datathrough a controller I/F 201, the print controller 202 temporarilystores them in an RAM 204. The print controller 202 causes an imageprocessing controller 205 to convert the stored image data into printdata so that the print head 8 can use the stored image data in a printoperation. After the print data is generated, the print controller 202causes the print head 8 to perform a print operation based on the printdata through a head I/F 206. In doing so, the print controller 202conveys a print medium S by driving the feed unit 6A or 6B, theconveying rollers 7, the discharge roller 12, and the flapper 11, whichare illustrated in FIG. 1, through a conveyance control unit 207. Aprint process is performed by performing a print operation with theprint head 8 in combination with the operation of conveying the printmedium S in accordance with instructions from the print controller 202.

A head carriage control unit 208 changes the orientation and position ofthe print head 8 in accordance with the operation state of the printingapparatus 1 such as a maintenance state or a print state. An ink supplycontrol unit 209 controls the ink supply unit 15 such that the pressureof the inks to be supplied to the print head 8 fall within anappropriate range. A maintenance control unit 210 controls the operationof the cap unit 10 and the wiping unit 17 of the maintenance unit 16when a maintenance operation is performed on the print head 8. A counter211 counts a predetermined time during maintenance processes such as avacuum wiping process. A sensor 212 (detection unit) is disposed on theconveying path of print media S and configured to detect print media Sbeing conveyed.

For the scanner engine unit 300, the main controller 101 controlshardware resources in a scanner controller 302 by using the RAM 106 as awork area in accordance with programs and various parameters stored inthe ROM 107. As a result, various mechanisms of the scanner section 3are controlled. For example, the main controller 101 controls hardwareresources in the scanner controller 302 through a controller I/F 301such that a document loaded on the ADF by the user is conveyed through aconveyance control unit 304 and read by a sensor 305. Then, the scannercontroller 302 stores the read image data in an RAM 303. Meanwhile, byconverting the image data thus obtained into print data, the printcontroller 202 can cause the print head 8 to perform a print operationbased on the image data read by the scanner controller 302.

FIG. 3 illustrates the printing apparatus 1 in a print state. Incontrast to the standby state illustrated in FIG. 1, the cap unit 10 isseparated from the ejection opening surface 8 a of the print head 8, andthe ejection opening surface 8 a is facing the platen 9. In thisembodiment, the plane of the platen 9 is tilted at approximate 45degrees with respect to the horizontal direction, and the ejectionopening surface 8 a of the print head 8 at the print position is alsotilted at approximately 45 degrees with respect to the horizontaldirection so that the distance between the ejection opening surface 8 aand the platen 9 can be kept at a fixed distance.

When the print head 8 is moved from the standby position illustrated inFIG. 1 to the print position illustrated in FIG. 3, the print controller202 lowers the cap unit 10 to a retreat position illustrated in FIG. 3by using the maintenance control unit 210. As a result, the ejectionopening surface 8 a of the print head 8 is separated from a cap member10 a. Then, using the head carriage control unit 208, the printcontroller 202 turns the print head 8 by 45 degrees while adjusting itsheight level in the vertical direction, to thereby make the ejectionopening surface 8 a face the platen 9. The print controller 202 performsthe reverse of the above steps when moving the print head 8 from theprint position to the standby position after a print operation iscompleted.

Next, the conveying paths for print media S in the print section 2 willbe described. Upon input of a print command, the print controller 202firstly moves the print head 8 to the print position illustrated in FIG.3 by using the maintenance control unit 210 and the head carriagecontrol unit 208. The print controller 202 then drives the first feedunit 6A or the second feed unit 6B based on the print command and feedsa print medium S by using the conveyance control unit 207.

FIGS. 4A to 4C are views illustrating a conveying path used in a case offeeding an A4 print medium S stored in the first cassette 5A. The printmedium S stacked at the top in the first cassette 5A is separated fromthe second and lower print media by the first feed unit 6A and conveyedtoward a printing region P between the platen 9 and the print head 8while being nipped between some conveying rollers 7 and pinch rollers 7a. FIG. 4A illustrates a conveying state immediately before the leadingedge of the print medium S reaches the printing region P. The directionof travel of the print medium S is changed from the horizontal direction(x direction) to a direction tilted at approximately 45 degrees withrespect to the horizontal direction by the time the print medium Sreaches the printing region P after being fed by the first feed unit 6A.

At the printing region P, the inks are ejected toward the print medium Sfrom the plurality of ejection ports provided in the print head 8. Theplaten 9 supports the back surface of the region of the print medium Sto which the inks are to be applied, and the distance between theejection port surface 8 a and the print medium S is kept at a fixeddistance. After the inks are applied, the print medium S passes the leftside of the flapper 11, whose tip is tilted toward the right side, andis conveyed upward in the vertical direction of the printing apparatus 1along the guide 18 while being guided by some conveying rollers 7 andspurs 7 b. FIG. 4B illustrates a state where the leading edge of theprint medium S has passed the printing region P and is being conveyedupward in the vertical direction. The direction of travel of the printmedium S has been changed to the vertically upward direction by theconveying rollers 7 and spurs 7 b from the position of the printingregion P, which is tilted at approximately 45 degrees with respect tothe horizontal direction.

After being conveyed vertically upward, the print medium S is dischargedonto the discharge tray 13 by the discharge roller 12 and the spur 7 b.FIG. 4C illustrates a state where the leading edge of the print medium Shas passed the discharge roller 12 and is being discharged onto thedischarge tray 13. The print medium S after being discharged is held onthe discharge tray 13 in a state where its surface on which the imagewas printed by the print head 8 faces down.

FIGS. 5A to 5C are views illustrating a conveying path used in a case offeeding an A3 print medium S stored in the second cassette 5B. The printmedium S stacked at the top in the second cassette 5B is separated fromthe second and lower print media by the second feed unit 6B and conveyedtoward the printing region P between the platen 9 and the print head 8while being nipped between some conveying rollers 7 and pinch rollers 7a.

FIG. 5A illustrates a conveying state immediately before the leadingedge of the print medium S reaches the printing region P. Pluralities ofconveying rollers 7 and pinch rollers 7 a and the inner guide 19 aredisposed along the conveying path from the point at which the printmedium P is fed by the second feed unit 6B to the point at which theprint medium P reaches the printing region P. Hence, the print medium Pis conveyed to the platen 9 while being curved in an S-shape.

The subsequent part of the conveying path is the same as that in thecase with an A4 print medium S illustrated in FIG. 4B and FIG. 4C. FIG.5B illustrates a state where the leading edge of the print medium S haspassed the printing region P and is being conveyed upward in thevertical direction. FIG. 5C illustrates a state where the leading edgeof the print medium S has passed the discharge roller 12 and is beingdischarged onto the discharge tray 13.

FIGS. 6A to 6D illustrate a conveying path used in a case of performinga print operation on the back surface (second surface) of an A4 printmedium S (double-sided printing). In the case of performing double-sidedprinting, printing is performed on a first surface (front surface) andthereafter a print operation is performed on a second surface (backsurface). The conveyance steps for performing the first surface printingare the same as FIG. 4A, FIG. 4B, and FIG. 4C and description thereofwill therefore be omitted here. The conveyance steps following FIG. 4Cwill be described below.

After the print operation on the first surface by the print head 8 iscompleted and the trailing edge of the print medium S passes the flapper11, the print controller 202 rotates the conveying rollers 7 in theopposite direction to thereby convey the print medium S to the innerside of the printing apparatus 1. At this moment, the flapper 11 iscontrolled by an actuator not illustrated such that its tip is tiltedtoward the left side. Thus, the leading edge of the print medium S (thetrailing edge in the print operation on the first surface) passes theright side of the flapper 11 and is conveyed downward in the verticaldirection. FIG. 6A illustrates a state where the leading edge of theprint medium S (the trailing edge in the print operation on the firstsurface) is passing the right side of the flapper 11.

Thereafter, the print medium S is conveyed along the curved outercircumferential surface of the inner guide 19 and conveyed to theprinting region P between the print head 8 and the platen 9 again. Thistime, the second surface of the print medium S faces the ejection portsurface 8 a of the print head 8. FIG. 6B illustrates a conveyance stateimmediately before the leading edge of the print medium S reaches theprinting region P for the print operation on the second surface.

The subsequent part of the conveying path is the same as that for thefirst surface printing illustrated in FIG. 4B and FIG. 4C. FIG. 6Cillustrates a state where the leading edge of the print medium S haspassed the printing region P and is being conveyed upward in thevertical direction. At this moment, the flapper 11 is controlled by theactuator not illustrated to move to the position at which its tip istilted toward the right side. FIG. 6D illustrates a state where theleading edge of the print medium S has passed the discharge roller 12and is being discharged onto the discharge tray 13.

Next, the maintenance operation on the print head 8 will be described.As also described with reference to FIG. 1, the maintenance unit 16 inthis embodiment includes the cap unit 10 and the wiping unit 17 andoperates them with a predetermined timing to perform the maintenanceoperation.

FIG. 7 is a view of the printing apparatus 1 in the maintenance state.To move the print head 8 from the standby position illustrated in FIG. 1to a maintenance position illustrated in FIG. 7, the print controller202 moves the print head 8 upward in the vertical direction and movesthe cap unit 10 downward in the vertical direction. The print controller202 then moves the wiping unit 17 in the rightward direction in FIG. 7from its retreat position. The print controller 202 thereafter moves theprint head 8 downward in the vertical direction to thereby move it tothe maintenance position, at which the maintenance operation can beperformed.

Also, to move the print head 8 from the print position illustrated inFIG. 3 to the maintenance position illustrated in FIG. 7, the printcontroller 202 moves the print head 8 upward in the vertical directionwhile turning it by 45 degrees. The print controller 202 then moves thewiping unit 17 in the rightward direction from its retreat position. Theprint controller 202 thereafter moves the print head 8 downward in thevertical direction to thereby move it to the maintenance position, atwhich the maintenance operation by the maintenance unit 16 can beperformed.

FIG. 8A is a perspective view illustrating the maintenance unit 16 atits standby position. FIG. 8B is a perspective view illustrating themaintenance unit 16 at its maintenance position. FIG. 8A corresponds toFIG. 1, and FIG. 8B corresponds to FIG. 7. When the print head 8 is atits standby position, the maintenance unit 16 is at its standby positionillustrated in FIG. 8A and therefore the cap unit 10 is moved upward inthe vertical direction and the wiping unit 17 is housed in themaintenance unit 16. The cap unit 10 includes the cap member 10 a, whichis in a box shape extending in the y direction. With this brought intotight contact with the ejection port surface 8 a of the print head 8,the cap unit 10 can reduce evaporation of the inks through the ejectionports. The cap unit 10 also has a function of collecting the inksejected onto the cap member 10 a for preliminary ejection or the likeand sucking the collected inks with a suction pump 24 (described later).

On the other hand, at the maintenance position illustrated in FIG. 8B,the cap unit 10 is moved downward in the vertical direction and thewiping unit 17 is pulled out of the maintenance unit 16. The wiping unit17 includes two wiper units, namely a blade wiper unit 171 and a vacuumwiper unit 172. Wiping operation performed by these two wiper units keepfavorable the ejection performance of the ejection openings formed onthe ejection opening surface 8 a and also recover it.

In the blade wiper unit 171, blade wipers 171 a that wipe the ejectionport surface 8 a in the x direction are disposed along the y directionover a length corresponding to the region along which the ejection portsare aligned. To perform a wiping operation using the blade wiper unit171, the wiping unit 17 moves the blade wiper unit 171 in the xdirection with the print head 8 positioned at such a height level thatthe print head 8 can contact the blade wipers 171 a. With this movement,the blade wipers 171 a wipe the inks and the like attached to theejection port surface 8 a.

At the inlet of the maintenance unit 16 through which the blade wipers171 a are housed, a wet wiper cleaner 16 a is disposed which removes theinks attached to the blade wipers 171 a and applies a wetting liquid tothe blade wipers 171 a. Each time the blade wipers 171 a are housed intothe maintenance unit 16, the matters attached to the blade wipers 171 aare removed and the wetting liquid is applied thereto by the wet wipercleaner 16 a. Then, the next time the blade wipers 171 a wipe theejection port surface 8 a, the wetting liquid is transferred onto theejection port surface 8 a, thereby improving the lubricity between theejection port surface 8 a and the blade wipers 171 a.

On the other hand, the vacuum wiper unit 172 includes a flat plate 172 awith an opening portion extending in the y direction, a carriage 172 bcapable of moving in the y direction within the opening portion, and avacuum wiper 172 c mounted on the carriage 172 b. The vacuum wiper 172 cis disposed so as to be capable of wiping the ejection port surface 8 ain they direction with movement of the carriage 172 b. At the tip of thevacuum wiper 172 c, a suction port (opening 26 a described later) isformed which is connected to a suction pump 24. Thus, by moving thecarriage 172 b in they direction with the suction pump 24 actuated, theinks and the like attached to the ejection port surface 8 a of the printhead 8 are wiped by the vacuum wiper 172 c and sucked into the suctionport. In this operation, the flat plate 172 a and positioning pins 172 dprovided at opposite ends of its opening portion are used to positionthe vacuum wiper 172 c relative to the ejection port surface 8 a.

In this embodiment, it is possible to perform a first wiping process inwhich the wiping operation by the blade wiper unit 171 is performed butthe wiping operation by the vacuum wiper unit 172 is not performed and asecond wiping process in which both wiping processes are sequentiallyperformed. To perform the first wiping process, the print controller 202first pulls the wiping unit 17 out of the maintenance unit 16 with theprint head 8 retreated to above the maintenance position in FIG. 7 inthe vertical direction. The print controller 202 then moves the printhead 8 downward in the vertical direction to such a position that theprint head 8 can contact the blade wipers 171 a, and thereafter movesthe wiping unit 17 to the inside of the maintenance unit 16. With thismovement, the blade wipers 171 a wipe the inks and the like attached tothe ejection port surface 8 a. Specifically, the blade wipers 171 a wipethe ejection port surface 8 a as they are moved from the position towhich the wiping unit 17 has been pulled out of the maintenance unit 16to the inside of the maintenance unit 16.

After housing the blade wiper unit 171, the print controller 202 movesthe cap unit 10 upward in the vertical direction to thereby bring thecap member 10 a into tight contact with the ejection port surface 8 a ofthe print head 8. The print controller 202 then drives the print head 8in this state to cause it to perform preliminary ejection, and sucks theinks collected in the cap member 10 a with the suction pump 24.

On the other hand, to perform the second wiping process, the printcontroller 202 first slides the wiping unit 17 to pull it out of themaintenance unit 16 with the print head 8 retreated to above themaintenance position in FIG. 7 in the vertical direction. The printcontroller 202 then moves the print head 8 downward in the verticaldirection to such a position that the print head 8 can contact the bladewipers 171 a, and thereafter moves the wiping unit 17 to the inside ofthe maintenance unit 16. As a result, the wiping operation by the bladewipers 171 a is performed on the ejection port surface 8 a.Subsequently, the print controller 202 slides the wiping unit 17 to pullit out of the maintenance unit 16 to a predetermined position with theprint head 8 retreated to above the maintenance position in FIG. 7 inthe vertical direction again. The print controller 202 then positionsthe ejection port surface 8 a and the vacuum wiper unit 172 relative toeach other by using the flat plate 172 a and the positioning pins 172 dwhile lowering the print head 8 to the maintenance position illustratedin FIG. 7. The print controller 202 thereafter performs theabove-described wiping operation by the vacuum wiper unit 172. The printcontroller 202 retreats the print head 8 upward in the verticaldirection and houses the wiping unit 17, and then performs preliminaryejection into the cap member and the operation of sucking the collectedinks with the cap unit 10, as in the first wiping process.

Next, a detailed configuration of the vacuum wiper unit 172 and detailsof the wiping operation performed by the vacuum wiper unit 172 will bedescribed with reference to FIGS. 9A to 15.

The wiping operation using the vacuum wiper unit 172 (hereinafterreferred to as “vacuum wiping” or a “vacuum wiping operation” asappropriate) is executed, as described above, after the wiping operationwith the blade wiper unit has finished in the second wiping process. Inthe present embodiment, this vacuum wiping operation (suction wipingoperation) is executed at the timing according to the purpose of removaland based on the process condition according to the purpose of removal.However, the present invention also includes a configuration in whichonly the vacuum wiping operation is performed alone without executingthe wiping operation with the blade wiper unit.

(Configuration of Vacuum Wiper 172 c)

First the configuration of the vacuum wiper 172 c will be described withreference to FIGS. 9A and 9B. FIG. 9A is a diagram illustrating thevacuum wiper 172 c mounted on the carriage 172 b. FIG. 9B is across-sectional view of the vacuum wiper 172 c taken along line IXB-IXBin FIG. 9A.

The vacuum wiper 172 c (wiping unit) has an opening (opening 26 adescribed later) adapted to come into contact with the ejection openingsurface 8 a and apply negative pressure to it and is capable of wipingthe ejection opening surface 8 a by moving in the forward direction(−y-direction). The vacuum wiper 172 c includes an elastic member 26which comes into contact with the ejection opening surface 8 a of theprint head 8 (printing unit) and a support member 28 which supports theelastic member 26.

The support member 28 extends in the z-direction and has a hollowprotrusion 28 a the upper end 28 aa of which is open. The support member28 is connected to the suction pump 24 (suction unit) via a tube 22 andother parts (see FIG. 11A), and the inside of the protrusion 28 a isdepressurized by the suction pump 24 driven under the control of theprint controller 202. The support member 28 is configured to be movablein the z-direction within a predetermined range and is always urged inthe arrow-A direction by an urging member 30 such as a spring.

With this configuration, in the case where the ejection opening surface8 a comes into contact with the vacuum wiper 172 c, the vacuum wiper 172c moves in the arrow-B direction against the urging force of the urgingmember 30. Thus, in the state where the vacuum wiper 172 c and theejection opening surface 8 a are in contact with each other, the vacuumwiper 172 c presses the ejection opening surface 8 a with the urgingforce of the urging member 30.

A protrusion 28 a of the support member 28 is inserted and fitted insidethe elastic member 26. The elastic member 26 extends in the z-directionand is designed such that the upper end of the elastic member 26 islocated higher than the upper end 28 aa of the protrusion 28 a. Notethat the positional relationship between the vacuum wiper 172 c and theprint head 8 in the z-direction is adjusted such that in the case wherethe vacuum wiper 172 c and the ejection opening surface 8 a come intocontact with each other, the elastic member 26 comes into contact withthe ejection opening surface 8 a but the support member 28 does not.

The elastic member 26 is formed of, for example, rubber or the likewhich is a material that does not cause or is less likely to causedamage to the ejection opening surface 8 a and an ejection unit 81 (seeFIG. 12B) provided on the ejection opening surface 8 a even though theelastic member 26 moves being in contact with the ejection openingsurface 8 a. The elastic member 26 has the opening 26 a at its upperend. In the state where the vacuum wiper 172 c is in contact with asuction preparation surface Bab (described later) of the ejectionopening surface 8 a, the opening 26 a is closed by the suctionpreparation surface 8 ab. The opening 26 a is inclined in thex-direction at a predetermined angle.

Next the movement mechanism of the carriage 172 b on which the vacuumwiper 172 c is mounted will be described with reference to FIGS. 10A and10B. FIG. 10A is an enlarged view of one end and its vicinities of anopening 172 aa of a flat plate 172 a on which the carriage 172 b islocated. FIG. 10B is a schematic configuration diagram of a movementmechanism of the carriage 172 b. In the present embodiment, the movementmechanism of the carriage 172 b, including the carriage 172 b itself,functions as a moving unit of the vacuum wiper 172 c. Note that thismoving unit may include, for example, the movement mechanism of theprint head 8.

In the vacuum wiper unit 172, the carriage 172 b on which the vacuumwiper 172 c is mounted is slidably provided on a pair of guide rails 172e extending in the y-direction. This carriage 172 b moves back and forthin the y-direction by a motor 32 driven based on the control of theprint controller 202. Specifically, the carriage 172 b moves in theforward direction which is a direction from one end of the opening 172aa in the flat plate 172 a toward the other end and also moves in thebackward direction which is a direction from the other end toward theone end. Thus the vacuum wiper 172 c mounted on the carriage 172 b isconfigured to be movable in the forward and backward directions of they-direction via the carriage 172 b. In the present embodiment, thevacuum wiping operation is performed only while the vacuum wiper 172 cis moving in the forward direction (a predetermined direction) via thecarriage 172 b. Note that in the present embodiment, the carriage 172 bis positioned at the other end of the opening 172 aa while the casewhere the carriage 172 b is not executing vacuum wiping operation.

The motor 32 is connected to a pulley 36 via gears 34. The pulley 36 islocated at an end portion of the other end side of the opening 172 aa,and a belt 40 is provided in a tensioned state between the pulley 36 andan idler pulley 38 located at an end portion of the one side of theopening 172 aa. Thus the belt 40 rotates driven by the motor 32. Thebelt 40 is arranged to extend in the y-direction. The carriage 172 b isfixed to the belt 40. Thus the rotation of the belt 40 moves thecarriage 172 b along the guide rails 172 e, and the rotation directionof the belt 40 determines the moving direction of the carriage 172 b.The motor 32 is connected to a rotary encoder 33 capable of detectingthe amount of rotation, the rotation direction, and the like of themotor 32. The print controller 202 detects the moving direction, themoving distance, and the like of the carriage 172 b based on detectionresults by this rotary encoder 33.

Next a suction mechanism of the vacuum wiper 172 c will be describedwith reference to FIGS. 11A and 11B. FIG. 11A is a schematicconfiguration diagram illustrating the suction mechanism connected viathe tube 22 to the vacuum wiper 172 c mounted on the carriage 172 b.FIG. 11B is a configuration diagram schematically illustrating thesuction mechanism in FIG. 11A.

The vacuum wiper 172 c mounted on the carriage 172 b is connected to thesuction mechanism including the suction pump 24 via the tube 22. Thesuction mechanism includes the suction pump 24, a motor 42 that drivesthe suction pump 24, and a buffer tank 44 (tank) the internal space ofwhich is adapted to be depressurized by the suction pump 24. The suctionmechanism also includes a waste ink tank 48 connected to the buffer tank44 via a flow path 46 and a pressure sensor 50 (pressure detection unit)capable of measuring the pressure inside the buffer tank 44.

The suction pump 24 is provided on the flow path 46 connecting thebuffer tank 44 and the waste ink tank 48. The motor 42 which drives thesuction pump 24 is controlled by the print controller 202. Under thecontrol of the print controller 202, the motor 42 drives the suctionpump 24 to depressurize the buffer tank 44. During the operation, theprint controller 202 monitors the pressure inside the buffer tank 44with the pressure sensor 50, and when the pressure reaches apredetermined pressure, the print controller 202 stops the suction pump24 via the motor 42.

A valve 52 is provided at a point on the tube 22 which connects thevacuum wiper 172 c and the buffer tank 44. Thus, in the state where thevalve 52 is open, the buffer tank 44 communicates with the vacuum wiper172 c via the tube 22, and in the state where the valve 52 is closed,the buffer tank 44 does not communicate with the vacuum wiper 172 c viathe tube 22. Ink, foreign objects, and the like sucked from the vacuumwiper 172 c by vacuum wiping are collected via the tube 22, the buffertank 44, and other parts into the waste ink tank 48. Note that thesuction pump 24 is also connected to the cap unit 10 (cap) via a tube(not illustrated) and thus is capable of sucking ink collected in thecap member 10 a. Thus, by opening or closing the valve 52, the suctionpump 24 performs sucking on one of the vacuum wiper 172 c and the capunit 10.

(Vacuum Wiping Process)

Execution of vacuum wiping using the vacuum wiper unit 172 with theconfiguration above will be described. FIG. 12A is a diagramillustrating the ejection opening surface 8 a of the print head 8brought into contact with the vacuum wiper 172 c at the start of vacuumwiping. FIG. 12B is a diagram illustrating the suction preparationsurface 8 ab, adapted to come into contact with the vacuum wiper 172 cat the start of vacuum wiping, and its vicinities on the ejectionopening surface 8 a. FIG. 12C is a diagram illustrating the vacuum wiper172 c that has come into contact with the suction preparation surface 8ab. FIG. 12D is a diagram illustrating the vacuum wiper 172 c moved inthe forward direction from the state illustrated in FIG. 12C by apredetermined distance. Note that the vacuum wiper 172 c is simplifiedin the illustrations of FIGS. 12C and 12D. FIG. 13 is a graphillustrating the fluctuation of the pressure value in the buffer tankduring vacuum wiping operation. FIG. 14 is a flowchart illustratingdetailed process procedure of a vacuum wiping process in the secondwiping process.

In the second wiping process, after a wiping process using the bladewiper unit 171 is performed, a vacuum wiping process is performed inwhich a vacuum wiping operation using the vacuum wiper unit 172 isexecuted. In the following description, the vacuum wiping process willbe described in detail.

When the vacuum wiping process starts, first the carriage 172 b is movedto a wiping start position illustrated in FIG. 8B, and the carriage 172b is moved in the forward direction until it hits a stopper to find itshome position and then moved in the backward direction to the wipingstart position. After that, the print head 8 is made to retreat to aposition higher in the vertical direction than the wiping position inFIG. 7 (S1402), and the wiping unit 17 is slid and pulled out from themaintenance unit 16 to a predetermined position (S1404). Thepredetermined position is a position at which the vacuum wiper 172 ccomes into contact with the suction preparation surface Bab in the casewhere the print head 8 is moved down to the wiping position, and atwhich the vacuum wiper 172 c can perform vacuum wiping for the ejectionopenings of the ejection unit 81 by moving in the forward direction.

After that, the print controller 202 moves down the print head 8 to thewiping position illustrated in FIG. 7 (S1406). In this state, thecarriage 172 b is positioned at the wiping start position which is atthe end on the one end side of the opening 172 aa, and the vacuum wiper172 c mounted on the carriage 172 b is in contact with the suctionpreparation surface Bab of the ejection opening surface 8 a (see FIG.12A). Also at this time, the vacuum wiper 172 c moves in the arrow-Cdirection against the urging force of the urging member 30, and thevacuum wiper 172 c is pressed against the suction preparation surfaceBab at a predetermined pressure by the urging force.

Next, the print controller 202 drives the motor 32 to move the vacuumwiper 172 c via the carriage 172 b with the vacuum wiper 172 c incontact with the ejection opening surface 8 a in the forward direction,in which the vacuum wiper 172 c moves during vacuum wiping, by apredetermined distance, and then the print controller 202 stops it there(S1408). After that, in the state where the suction pump 24 and thevacuum wiper 172 c are connected by the valve 52, the motor 42 is drivento make the suction pump 24 perform sucking (negative pressureapplication) until the pressure inside the buffer tank 44 reaches a setvalue (S1410). This operation also depressurizes the inside of thevacuum wiper 172 c communicating with the buffer tank 44. The set value(first value) is set based on a predetermined negative pressure value(second value) set according to the process condition described later.In the present embodiment, the set value is set to a negative pressurevalue higher than the predetermined negative pressure value.

At this time, when the print head 8 is moved down, the vacuum wiper 172c comes into contact with the ejection opening surface 8 a such that theentire upper end surface 26 b (top surface) of the elastic member 26comes into contact with the suction preparation surface Bab asillustrated in FIG. 12C. In this state, the urging force per unit areaof the upper end surface 26 b in contact with the suction preparationsurface Bab is low, and accordingly, the contact portions may notconform to minute irregularities at the opening 26 a of the elasticmember 26 or on the suction preparation surface 8 ab. Consequently, atthe negative pressure application to the buffer tank 44, outside aireasily enter from between the vacuum wiper 172 c and the suctionpreparation surface 8 ab.

In the present embodiment, before suction by the suction pump 24 isstarted, the vacuum wiper 172 c is moved in the forward direction by apredetermined distance with the vacuum wiper 172 c in contact with thesuction preparation surface 8 ab. This operation makes the edges of theupper end surface 26 b of the elastic member 26 in contact with thesuction preparation surface Bab as illustrated in FIG. 12D. In thisstate, the contact area between the suction preparation surface Bab andthe upper end surface 26 b is smaller, and accordingly, the urging forceper unit area of the upper end surface 26 b in contact with the suctionpreparation surface Bab is greater. This enables the contact portions toconform to minute irregularities at the opening 26 a of the elasticmember 26 or on the suction preparation surface 8 ab, reducing outsideair entering from between the vacuum wiper 172 c and the suctionpreparation surface Bab at the negative pressure application to thebuffer tank 44.

Hence the above predetermined distance is set to a moving distance thatchanges the state where the entire upper end surface 26 b of the elasticmember 26 is in contact with the suction preparation surface Bab intothe state where edges of the upper end surface 26 b are in contact withthe suction preparation surface 8 ab. Since the predetermined distancevaries depending on the shape, material, and other factors of theelastic member 26 of the vacuum wiper 172 c, the predetermined distanceis determined, for example, experimentally.

When the buffer tank 44 is depressurized to the set value by thenegative pressure application, the print controller 202 stops the motor42 to stop the suction of the suction pump 24 (S1412). After that, theprint controller 202 moves the vacuum wiper 172 c via the carriage 172 bin the forward direction with the vacuum wiper 172 c in contact with theejection opening surface 8 a and performs vacuum wiping for the ejectionopenings arranged on the ejection opening surface 8 a of the ejectionunit 81 (S1414). Note that the moving speed of the vacuum wiper 172 c atS1414 is determined based on the moving speed set according to theprocess condition described later.

Here, on the ejection opening surface 8 a are provided the ejection unit81, a frame 82, a sealing portion 83, and a wiring sealing portion 84.The ejection unit 81 is disposed on the sealing portion 83, and thus thewiring connected to the ejection unit 81 is sealed by the wiring sealingportion 84. The sealing portion 83 is recessed relative to the ejectionunit 81 and the frame 82. The wiring sealing portion 84 protrudesrelative to the ejection unit 81 and the frame 82. Each ejection unit 81is arranged to be inclined relative to the moving direction of thevacuum wiper 172 c (the y-direction).

Note that the vacuum wiper 172 c is pressed against the ejection openingsurface 8 a by the urging member 30. Thus the vacuum wiper 172 c canconform to the above irregularities on the ejection opening surface 8 ato some extent. However, multiple ejection units 81 are arrayed in themoving direction, and there are some points where the vacuum wiper 172 ccannot conform to the ejection opening surface 8 a due to the movingspeed or other factors. Thus outside air flows in from the opening 26 aof the vacuum wiper 172 c. In the present embodiment, since the insideof the vacuum wiper 172 c is depressurized to the set value along withthe buffer tank 44, even though outside air flows in from the opening 26a, the negative pressure acting on the ejection openings and the like atthe opening 26 a will not suddenly decrease. However, along with themovement of the vacuum wiper 172 c, the pressure inside the vacuum wiper172 c and the buffer tank 44 gradually increases.

To address this situation, it is determined in the present embodimentwhether the pressure inside the buffer tank 44 has reached thepredetermined negative pressure value during the movement of the vacuumwiper 172 c in the forward direction (S1416). Specifically, at S1416, itis determined whether the pressure inside the buffer tank 44 hasdecreased to the predetermined negative pressure value along with themovement of the vacuum wiper 172 c. As described above, thepredetermined negative pressure value is a pressure higher than the setvalue at the negative pressure application to the buffer tank 44 (thenegative pressure value is smaller). Note that the predeterminednegative pressure value is set according to the process conditiondescribed later.

If the print controller 202 determines at S1416 that the pressure insidethe buffer tank 44 detected by the pressure sensor 50 has reached thepredetermined negative pressure value, the print controller 202 drivesthe motor 42 to resume suction of the suction pump 24 (S1418). Note thatalso during the process at S1418, the vacuum wiper 172 c is moving inthe forward direction. After that, it is determined whether the pressureinside the buffer tank 44 has reached the set value (S1420). If it isdetermined that it has reached the set value, the suction pump 24 isstopped (S1422), and the process proceeds to S1424 described later. Notethat the determination at S1416 is made by the print controller 202based on the detection results by the pressure sensor 50. In summary, inthe present embodiment, control is performed to drive or stop thesuction pump 24 during the vacuum wiping (during the suction wipingoperation) so that the pressure inside the buffer tank 44 is controlledto be kept within the predetermined range (between the predeterminednegative pressure value and the set value) (see FIG. 13).

On the other hand, if it is determined at S1416 that the pressure insidethe buffer tank 44 has not reached the predetermined negative pressurevalue, it is determined whether the carriage 172 b has moved to a vacuumwiping end position set in advance (S1424). The determination at S1424is made by the print controller 202 based on the detection results bythe rotary encoder 33.

If it is determined at S1424 that the carriage 172 b has not moved tothe vacuum wiping end position, the process returns to S1416. On theother hand, if it is determined at S1424 that the carriage 172 b hasmoved to the vacuum wiping end position, this vacuum wiping processends.

In the case where the vacuum wiping process ends as above, the printcontroller 202 makes the print head 8 retreat upward in the verticaldirection.

(Execution Management of Vacuum Wiping)

In the present embodiment, the negative pressure value and the operationtime (the moving speed) during vacuum wiping are made differentdepending on the purposes of removal, in other words, depending onobjects to be removed by the vacuum wiping. There are three casesregarding the purposes of removal, shown below. A first case is onewhere foreign objects attached in the vicinities of the ejectionopenings or pushed into the ejection openings are to be removed(hereinafter referred to as “removal of foreign objects” asappropriate), and in this case, the objects to be removed are foreignobjects. Another case is one where ink thickened in the ejectionopenings is to be removed (hereinafter “removal of thickened ink” asappropriate), and in this case, the object to be removed is thickenedink. Still another case is one where bubbles that have occurred in theejection openings are to be removed (hereinafter referred to as “removalof bubbles” as appropriate), and in this case, the objects to be removedare bubbles. The timing at which the vacuum wiping process is to beperformed and the process condition for the vacuum wiping process areset according to each purpose of removal, in other words, the objects tobe removed by the vacuum wiping.

Specifically, for removal of thickened ink, ink thickened in thevicinities of the ejection openings within the ejection openings is tobe removed. In other words, since in this case, only thickened ink needsto be pulled out from the ejection openings, ejecting condition can berecovered by only applying a low negative pressure for a short timeperiod. For this reason, the process condition for removal of thickenedink (hereinafter referred to as the “first condition”) is set asfollows: the negative pressure value, small; the moving speed, high(high-speed). Note that the negative pressure value and the moving speedin the first condition and a second condition and third conditiondescribed later show relative magnitude relationship between the processconditions for the three removal purposes.

In the case where an irregular termination occurs in which printoperation ends without being able to cap the ejection opening surface 8a with the cap unit 10, and the ejection opening surface 8 a is leftunprotected (uncovered) with the cap unit 10 for a first time period ormore, ink thickening occurs in the ejection openings. In the presentembodiment, in the case where the time after an irregular terminationoccurs with the cap open until an irregular solving process is executedand print operation is ready to start again is less than the first timeperiod, vacuum wiping is executed based on the first condition. Thefirst time period (first threshold) can be set to, for example, apredetermined time period longer than or equal to five minutes andshorter than six hours. Note that in the case where the first timeperiod is six hours or longer, for example, suction is performed usingthe cap unit 10. Suction using the cap unit 10 is more powerful thanvacuum wiping and is accordingly capable of removing more thickened ink.

For removal of bubbles, in order to pull bubbles that have occurred inflow paths of the ejection openings out of the ejection openings, arelatively high negative pressure needs to be applied for a long time.For this reason, the process condition for removal of bubbles(hereinafter referred to as the “second condition”) is set as follows:the negative pressure value, middle; the moving speed, low (low-speed).

Bubbles that have occurred in ink grow over time. Hence, in the casewhere it is determined that a second time period has passed since thelast-executed vacuum wiping, vacuum wiping is executed based on thesecond condition. The second time period (second threshold) variesdepending on used ink, the configuration of the print head 8, and otherfactors and thus is determined experimentally. For example, in the casewhere it is determined that the ejection opening surface 8 a has beencapped with the cap unit 10 for 30 days (720 hours) or more, vacuumwiping is executed based on the second condition.

For removal of foreign objects, in order to remove foreign objects suchas paper dust attached in the vicinities of the ejection openings orpushed into the ejection openings, high negative pressure is necessaryalso to pull the foreign objects out of the ejection openings. Note thatbecause foreign objects are often positioned in the vicinities of theejection openings and hence are easier to be pulled out than bubblesthat have occurred in the flow paths of the ejection openings, theoperation time can be relatively short. For this reason, the processcondition for removal of foreign objects (hereinafter referred to as the“third condition”) is set as follows: the negative pressure value,large; the moving speed, middle (middle-speed).

The amount of attached foreign objects such as paper dust increases asthe number of conveyed print media increases. For this reason, in thecase where it is determined that the number of conveyed print media hasreached a predetermined number, vacuum wiping is executed based on thethird condition. The predetermined number is set to, for example, 5000.However, the predetermined number may be set as appropriate according tothe type of print media to be used, the configuration of the conveyingpath of the printing apparatus, and other factors.

In the present embodiment, when a first print operation is performed inthe printing apparatus 1, a management process starts for managingexecution of vacuum wiping (the second wiping process). Note that thismanagement process is executed in parallel with various processes suchas printing process for performing printing on print media, for example.FIG. 15 is a flowchart illustrating detailed process procedure of themanagement process.

When the management process starts, first the print controller 202starts counting time with the counter 211, and also the print controller202 starts counting the number of conveyed print media based on thedetection results by the sensor 212 (S1502). Note that a first countvalue counted by the counter 211 at S1502 is initialized after thevacuum wiping process is executed, as described later. Hence the firstcount value indicates the time elapsed since the last (latest) vacuumwiping process.

Next it is determined whether the number of conveyed media has reachedthe predetermined number (for example, 5000) (S1504). The process atthis S1504 is a process for determining whether to execute removal offoreign objects by vacuum wiping. At S1504, the print controller 202determines whether a second count value counted based on the detectionresults by the sensor 212 (the count value of the number of conveyedmedia) has reached, for example, “5000”.

If it is determined at S1504 that the number of conveyed media hasreached the predetermined number, in other words, that removal offoreign objects should be executed, the second wiping process isexecuted (S1506). In this case, the vacuum wiping process is executed inthe above third condition. Specifically, in the case where it isdetermined that the removal of foreign objects should be executed byvacuum wiping, the value of the negative pressure applied to theejection opening surface 8 a and the moving speed of the vacuum wiper172 c are determined according to the third condition set in advance.Note that in the case where print operation is being performed based ona predetermined job when it is determined that the number of conveyedmedia has reached the predetermined number, the print operation may bestopped to execute the second wiping process, or the second wipingprocess may be executed after the print operation according to the jobfinishes.

Specifically, in the third condition, for example, the predeterminednegative pressure value is set to −50 kPa; the moving speed is set to 7mm/s. The set value is set to, for example, −60 kPa. Thus, in the vacuumwiping process in the second wiping process executed at S1506, thenegative pressure application is performed at S1410 such that thepressure inside the buffer tank 44 becomes −60 kPa. At S1414, the vacuumwiper 172 c is moved in the forward direction at 7 mm/s. At S1416, it isdetermined whether the pressure inside the buffer tank 44 has reached−50 kPa. At S1420, it is determined whether the pressure inside thebuffer tank has reached −60 kPa.

After that, it is determined whether the second wiping process hasfinished (S1508), and if it is determined that it has finished, thefirst and second count values are initialized (S1510), and the processproceeds to S1502.

Then, if it is determined at S1504 that the number of conveyed media hasnot reached the predetermined number, in other words, that removal offoreign objects should not be executed, it is determined whether anirregular termination has occurred in which operation ends without beingable to cap the ejection opening surface 8 a with the cap unit 10(S1512). This S1512 and S1518 described later are processes fordetermining whether to execute removal of thickened ink by vacuumwiping. Note that the determination process at S1512 is executed by theprint controller 202 based on the detection results by various sensorsprovided in the printing apparatus 1.

If it is determined at S1512 that an irregular termination has occurredwith the cap open, the counter 211 starts counting the time elapsedsince the irregular termination (S1514). Next it is determined whetheran irregular termination solving process has finished (S1516). Note thatthe determination whether the irregular termination solving process hasfinished is made by the print controller 202, for example, based on thedetection results by various sensors provided in the apparatus, an inputfrom the user, or other information.

If it is determined at S1516 that the irregular termination solvingprocess has finished, it is determined whether a third count valueindicating the time elapsed since the irregular termination has reachedthe first time period (S1518). Note that the first time period is a timeperiod as a criterion for vacuum wiping for the purpose of removal ofthickened ink and is set, for example, to a predetermined time period offive minutes or longer and shorter than six hours. If it is determinedat S1518 that the third count value has not reached the first timeperiod, the process returns to S1504.

If it is determined at S1518 that the third count value has reached thefirst time period, in other words, that removal of thickened ink shouldbe executed, the second wiping process is executed (S1520). In thiscase, the vacuum wiping process is executed in the above firstcondition. In other words, if it is determined that removal of thickenedink should be executed by vacuum wiping, the value of the negativepressure applied to the ejection opening surface 8 a and the movingspeed of the vacuum wiper 172 c are determined according to the firstcondition set in in advance.

Specifically, in the first condition, for example, the predeterminednegative pressure value is set to −10 kPa; the moving speed is set to 10mm/s. The set value is set to, for example, −15 kPa. Thus, in the vacuumwiping process in the second wiping process executed at S1520, thenegative pressure application is performed at S1410 such that thepressure inside the buffer tank 44 becomes −15 kPa. At S1414, the vacuumwiper 172 c is moved in the forward direction at 10 mm/s. At S1416, itis determined whether the pressure inside the buffer tank 44 has reached−10 kPa. At S1420, it is determined whether the pressure inside thebuffer tank has reached −15 kPa.

After that, it is determined whether the second wiping process hasfinished (S1522), and if it is determined that it has finished, thefirst and third count values are initialized (S1524). Then the counter211 starts counting the time elapsed since the vacuum wiping process(S1526), and the process returns to S1504.

On the other hand, if it is determined at S1512 that an irregulartermination has not occurred, in other words, that removal of thickenedink should not be executed, it is determined whether the first countvalue indicating the time elapsed since the last vacuum wiping processhas reached the second time period (S1528). This S1528 is adetermination process executed by the print controller 202, which is aprocess performed for determining whether to execute removal of bubblesby vacuum wiping. The second time period is a time period as a criterionfor vacuum wiping for the purpose of removal of bubbles and is set, forexample, to 720 hours. If it is determined at S1528 that the first countvalue has not reached the second time period, in other words, thatremoval of bubble ink should not be executed, the process returns toS1504.

If it is determined at S1528 that the first count value has reached thesecond time period, in other words, that removal of bubble ink should beexecuted, the second wiping process is executed (S1530). In this case,the vacuum wiping process is executed in the above second condition. Inother words, if it is determined that removal of bubbles should beexecuted by vacuum wiping, the value of the negative pressure applied tothe ejection opening surface 8 a and the moving speed of the vacuumwiper 172 c are determined according to the second condition set inadvance.

Specifically, in the second condition, for example, the predeterminednegative pressure value is set to −20 kPa; the moving speed is set to 5mm/s. The set value is set to, for example, −28 kPa. Thus, in the vacuumwiping process in the second wiping process executed at S1530, thenegative pressure application is performed at S1410 such that thepressure inside the buffer tank 44 becomes −28 kPa. At S1414, the vacuumwiper 172 c is moved in the forward direction at 5 mm/s. At S1416, it isdetermined whether the pressure inside the buffer tank 44 has reached−20 kPa. At S1420, it is determined whether the pressure inside thebuffer tank has reached −28 kPa.

After that, it is determined whether the second wiping process hasfinished (S1532), and if it is determined that it has finished, thefirst count value is initialized (S1534). Then, the counter 211 startscounting the time elapsed since the vacuum wiping process (S1536), andthe process returns to S1504.

As has been described, the print controller 202 controls the movementand suction of the vacuum wiper 172 c in the present embodiment. Inaddition, the print controller 202 determines the timing for executingvacuum wiping and also determines the process condition in the vacuumwiping based on the determination results. In other words, in thepresent embodiment, the print controller 202 functions as a control unitthat performs various kinds of control on the vacuum wiping operationsuch as controlling the movement and suction of the vacuum wiper 172 c,determining the timing for vacuum wiping, and determining the processcondition.

As has been described above, in the printing apparatus 1, the vacuumwiping process is executed at the timing according to the purpose ofremoval in the process condition according to the purpose of removal.This enables the printing apparatus 1 to execute efficient vacuum wipingprocesses according to the purposes of removal. This also reduces theamount of waste ink. Accordingly, the waste ink tank 48 can bedownsized, contributing to downsizing of the printing apparatus 1.

In addition, the printing apparatus 1 has the buffer tank 44communicating with the vacuum wiper 172 c, and the suction pump 24 isdriven based on the pressure value inside the buffer tank 44. Because ofthe buffer tank 44, even though outside air flows in from the opening 26a of the vacuum wiper 172 c, the negative pressure acting on theejection opening surface 8 a does not suddenly decrease, thus providinga stable effect of vacuum wiping.

Further, in the printing apparatus 1, when the buffer tank 44 isdepressurized to the set value by the negative pressure application tothe buffer tank 44, the suction pump 24 is stopped. After that, thevacuum wiper 172 c is moved in the forward direction. When the pressureinside the buffer tank 44 increases to the predetermined negativepressure value, the suction pump 24 is driven to depressurize the insideof the buffer tank 44 to the set value while the vacuum wiper 172 c ismoving in the forward direction. This operation prevents the suctionforce of vacuum wiping from differing largely between the start and endof vacuum wiping. This operation also reduces the driving time of thesuction pump 24, which in turn reduces the power consumption, making theexecution of the vacuum wiping operation efficient.

In addition, in the printing apparatus 1, after the vacuum wiper 172 cand the suction preparation surface Bab of the ejection opening surface8 a are brought into contact with each other, the vacuum wiper 172 c ismoved in the forward direction by a predetermined distance. Thisoperation ensures the close contact between the upper end surface 26 bof the vacuum wiper 172 c and the suction preparation surface 8 ab, andthus making the execution of the negative pressure application to thebuffer tank 44 efficient.

Other Embodiments

Note that the above embodiment may be modified as shown in the following(1) to (4).

(1) Although in the present embodiment, the vacuum wiping process isperformed for the three purposes of removal, in respective differentprocess conditions, the present disclosure is not limited to thisoperation. Specifically, the vacuum wiping process may be performed fortwo or four or more purposes of removal, in respective different processconditions.

(2) In the above embodiment, the vacuum wiper 172 c is moved relative tothe ejection opening surface 8 a in vacuum wiping. In addition, thevacuum wiper 172 c is brought into contact with the ejection openingsurface 8 a by pulling the wiping unit 17 out of the maintenance unit 16and moving the print head 8 to the wiping position. However, therelationship between the movements of the print head 8 and the vacuumwiper 172 c is not limited to these operations. In other words, anyconfiguration is possible as long as the print head 8 and the vacuumwiper 172 c can move relative to each other.

(3) Although in the above embodiment, printing is performed on printmedia conveyed by the printing apparatus 1, the present disclosure isnot limited to this configuration. Specifically, a configuration may besuch that the printing apparatus 1 performs printing by ejecting inkfrom the print head onto print media placed at a predetermined position.Although in the above embodiment, vacuum wiping is performed only whilethe vacuum wiper 172 c moves in the forward direction, the presentdisclosure is not limited to this operation. Specifically, vacuum wipingmay be performed only while the vacuum wiper 172 c moves in the backwarddirection, or while it moves both in the forward direction and in thebackward direction.

(4) Although in the above embodiment, the timing for executing vacuumwiping is determined in the management process based on the conditionsset according to objects to be removed by the vacuum wiping, the presentdisclosure is not limited to this operation. Specifically, a detectionunit may be provided which is capable of detecting the state of theprint head 8, for example, whether ink thickening has occurred, whetherforeign objects have been attached to or pushed into the ejectionopenings, or whether bubbles have occurred, and the timing for executingvacuum wiping may be determined based on the detection results by thedetection unit.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2018-189626 filed Oct. 5, 2018, which is hereby incorporated byreference wherein in its entirety.

1.-16. (canceled)
 17. A printing apparatus comprising: a printing unithaving an ejection opening surface on which multiple ejection openingsconfigured to eject liquid are arrayed; a wiping unit capable of wipingthe ejection opening surface by moving in a predetermined directionrelative to the ejection opening surface; a suction unit connected tothe wiping unit and configured to apply negative pressure to theejection opening surface; a cap configured to cap the ejection openingsurface; and a control unit configured to perform suction wipingoperation by wiping the ejection opening surface with the wiping unitwhile driving the suction unit to apply negative pressure to theejection opening surface, wherein the suction wiping operation isperformed in a case where an elapsed time since the ejection openingsurface was left uncapped with the cap exceeds a threshold.
 18. Theprinting apparatus according to claim 17, wherein the control unitcontrols a moving speed of the wiping unit or strength of negativepressure in the suction wiping operation performed in a case where theelapsed time exceeds the threshold.
 19. The printing apparatus accordingto claim 17, further comprising a counter configured to count theelapsed time.
 20. The printing apparatus according to claim 17, furthercomprising a tank disposed between the wiping unit and the suction unitand configured to be depressurized by the suction unit.
 21. The printingapparatus according to claim 20, further comprising a pressure detectionunit configured to detect a pressure value of the pressure inside thetank.
 22. The printing apparatus according to claim 21, wherein beforestarting the suction wiping operation, the control unit drives thesuction unit until a pressure value detected by the pressure detectionunit reaches a first negative pressure value with the wiping unit incontact with a suction preparation surface that is part of the ejectionopening surface and on which the ejection openings are not arrayed. 23.The printing apparatus according to claim 22, wherein the control unitstarts the suction wiping operation by moving the wiping unit in thepredetermined direction at the moving speed determined, and in a casewhere the pressure value detected by the pressure detection unit reachesa second negative pressure value weaker than the first negative pressureduring the movement of the wiping unit in the predetermined direction,the control unit drives the suction unit until the pressure valuereaches the first negative pressure value.
 24. The printing apparatusaccording to claim 22, wherein the control unit brings the wiping unitinto contact with the suction preparation surface, moves the wiping unitin the predetermined direction by a predetermined distance, and thendrives the suction unit until the pressure value detected by thepressure detection unit reaches the first negative pressure value.
 25. Arecovery method used in a printing apparatus including a printing unithaving an ejection opening surface on which multiple ejection openingsconfigured to eject liquid are arrayed and a wiping unit for wiping theejection opening surface, the recovery method being for recoveringejection performance of the ejection openings by performing suctionwiping operation in which the wiping unit is being moved relative to theejection opening surface in a state where a suction unit is driven toapply negative pressure to the ejection opening surface, comprising:performing the section wiping operation in a case where an elapsed timesince the ejection opening surface was left uncapped with a capconfigured to cap the ejection opening surface exceeds a threshold.